Tips on how to disable default administrator Windows 7?
First some background: I acquired a well used computer from work (still attached to the domain) because nobody wants it anymore. We just got MacBooks, so an existing Windows computer is practically useless. While i got home, I messed around with the settings for quite a while, because I've never has a family computer before so I was just curious. I found something called UAC and turned it on (it turned out off). Now, whenever I try to try and do just about anything, Could not. I realized soon after turning it on it I am not saying the administrator, I just use a standard account. Could not delete the administrator account because I don't have admin access. Not a soul inside my work knows the account password anymore. I'm type of disappointed now because I am unable to install any programs or a single thing. I've tried practically everything, from setting up a new admin account (didn't have system access) to resetting the admin password (I couldn't do that either). I'd ask my boss if he could a single thing on the domain as a domain controller but he's simply too busy to worry about a well used computer. I'm desperate, so I'll try anything. Thank you!

Reset administrator password windows 7 with Windows Password Recovery Tool 3.0. It is a easy-to-use Windows 7 password remover tool that helps you create a disk within minutes. Just follow the steps below:
1. Login a pc that you can download something. Download Windows Password Recovery Tool Professional, install it with several clicks and then run it.
2. Burn a Windows 7 password reset disk with a blank CD/DVD or USB Flash Drive. A USB Flash Drive will be better if the locked Win 7 pc with the driver.
3. Connect the burned Win 7 password reset disk with the locked Win 7 computer, Press DELETE, F1, F2, F10, F12 or Alt+S (choose one or combined key that screen may display a sentence while computer starts), then set bios to boot pc from USB Flash Drive, restart pc and there will load software program.
4. Choose the user account that you need reset the unknown logon password, click "reset" button to begin password reset.
5. A message box will pop up, just click "Yes", then the login password will be reset a new one.
6. Shift out this Windows 7 password reset disk, restart PC with logon password problem. Now you will successfully logon Windows 7 without password after remove windows 7 administrator password.

Secondly: Check if the caps lock has been turned on - if it hasn't - type the password in one key at a time with one finger, slowly - I've found out that I had my fingers off one key on one hand, which made me enter the wrong password by whatever keys were being typed by that hand.

Thirdly: If the first one doesn't work - try using F8 to get into Safe Mode to see if you can remove the password.

Also, share the forth solution to all administrator, including default Administrator Windows 7, it will help them make good preparation before lost admin password: